| Objective:The research aims to study the expression of Glycogen synthase kinase 3?(GSK-3?) and Collapsin response mediator protein 2(CRMP-2)in the form deprivation amblyopic visual cortex of rats, and explores its' significance in the pathogenesis of amblyopia.Methods:1. In 64 healthy rats of born 14 day, 32 rats were randomly selected to using unilateral eyelid suture technique for form deprivation amblyopia group, and another 32 rats without any treatment to be the normal group.According to the born number of rats, all rats in form deprivation amblyopia group and the normal group rats at 21 day were underwent pattern visual evoked potential(P-VEP) detection after using anesthetized with 10% chloral hydrate. The latency and amplitude values of P100 wave were recorded to judge whether monocular form deprivation amblyopia was successfully established or not.2. According to the born number of rats, all rats in form deprivation amblyopia group and the normal group were respectively killed at four time points, which were 14 day, 21 day, 45 day and 120 day. 8 rats were killed at each time point. All sacrificed rats were removed the visual cortex tissue, which were used 4% paraformaldehyde PBS solution to fixed, then cut tissue slice after sealing wax. Firstly, HE(Hematoxylin Eosin) staining was used to observe the cell morphology of visual neurons in form deprivation amblyopia group and normal group.Secondly, SP immunohistochemical method was used to measure the expressions of GSK-3? and CRMP-2 on immunoreactive neurons in form deprivation amblyopia group and normal group, and the image analysis system was used to measure the average light density(AOD value) of GSK-3? and CRMP-2 immunoreactive neurons and made the statistical analysis.Results:1. Results of P-VEP detection: compared with form deprivation amblyopia group and normal group, P100 wave latency significantly prolonged(P<0.05), and amplitude rather decreased(P<0.05). It indicated that monocular deprivation amblyopia rat model could be established successfully through using the unilateral eyelid suture technique with seven days.2. HE staining results: the neuronal cells were densely distributed in visual cortex in rats of normal group.The outlines of cortical neuronal cells were clearly show in rats of normal group. And the morphology of the cortical neuronal cells could be easily distinguish. Otherwise the neuronal cells were sparsely distributed in visual cortex in rats of form deprivation amblyopia group. The arrangement of cortical neuronal cells were disordered in the form deprivation amblyopia group. The cell morphology were unable to clearly identify, and the cell body became more smaller. There appeared the phenomenon of nuclear pyknosis,basophilic, and part of the nuclear dissolution.3. Immunohistochemical results: 1) GSK-3? was expressed in visual cortex of rat. In the normal group, the expressions of GSK-3? in visual cortex of rats were no obvious difference at 14 day, 21 day, 45 day, 120day(P>0.05). But in the form deprivation group, the multiple comparisons of expressions of GSK-3? in the visual cortex of rats between 14 day, 21 day, 45 day, 120 day were different(P<0.05) except45 day and 120 day(P>0.05). Compared expressions of GSK-3? in the visual cortex of rats with form deprivation amblyopia group and normal group at 14 day, 21 day, 45 day, 120 day, the expressions in form deprivation amblyopia group is higher at 21 day, 45 day, 120 day(P<0.05)except at 14 day(P>0.05).2) CRMP-2 was expressed in visual cortex of rat. In the normal group, the multiple comparisons of expressions of CRMP-2 in the visual cortex of rats between 14 day, 21 day, 45 day, 120 day were different(P<0.05) except 45 day and 120 day(P>0.05). Similarly, in the form deprivation group, the multiple comparisons of expressions of CRMP-2in the visual cortex of rats between 14 day, 21 day, 45 day, 120 day were different(P<0.05) except 45 day and 120 day(P>0.05).3) The correlation between expressed GSK-3? and CRMP-2 in rat's visual cortex: in normal group there is not much correlation between expressed GSK-3? and CRMP-2 in rat visual cortex(r=-0.142, P=0.438),but in the form monocular deprivation group, it showed a negative correlation(r=-0.838, P=0.000).Conclusion1. Early in the critical period of visual development of rats, the monocular deprivation amblyopia rat model could be established successfully through using the unilateral eyelid suture technique with seven days.2. In the key period of visual development in normal rats, GSK-3?and CRMP-2 were expressed in the brain's visual cortex of rats. It indicated that both may be involved in visual development process.3. In visual cortex of form deprivation amblyopia rat,the expression of GSK-3? with deprivation increased gradually which reached its peak in 45 day, but the expression of CRMP-2 decreased gradually which reached low level in 45 day. The correlation between GSK-3? and CRMP-2 showed was negative. It indicated that there may be some regulation mechanism between GSK-3? and CRMP-2 in the plastically visual development, which may be involved in the occurrence and development of amblyopia. |
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